The present invention relates to refrigeration appliances and more particularly to a refrigeration system having a single evaporator for cooling multiple refrigeration compartments more efficiently.
In typical domestic refrigeration appliances, the appliance often times has two separate compartments which are maintained at different temperatures. For example, there may be a freezer compartment which has a temperature maintained below 0.degree. C. and a fresh food compartment which is maintained at a temperature somewhat above 0.degree. C. In many commercially available refrigeration devices a single evaporator is used with an evaporating pressure of approximately 0-2 PSIG. Air is circulated over the evaporator simultaneously from both the freezer compartment and the refrigerator compartment. This "mixed" air flow scheme results in dehumidification of the refrigerator compartment and subsequent frost build-up on the single evaporator coil, necessitating a periodic defrost cycle to get rid of the accumulated frost.
Also, using a single evaporator operating at a single evaporating pressure to provide the cooling for two compartments which are maintained at different temperatures results in an inefficient use of the refrigeration system for the higher temperature compartment.
U.S. Pat. No. 4,015,182 disclosed the use of a variable capacity DC ECM compressor and a single evaporator in an automobile air conditioner.
U.S. Pat. No. 4,916,916 discloses the use of a phase change energy storage material in connection with a multiple evaporator refrigeration system.